ENG and neoplasm: This marker is an indicator of endothelial cell proliferation and is up-regulated during angiogenesis.[12-14] Moreover, the expression of CD105 is one of the most conspicuous characteristics of newly formed blood vessels; its expression is negative or insignificant in previously formed blood vessels, endothelium of the vessels of normal tissues, and the endothelial cells of lymphatic vessels.[15] Some studies showed that CD105 antibody had higher specificity for tumor vessels comparing the other endothelial markers such as: von Willebrand, CD31, CD34 and factor VIII.